The application of silicon dioxide is widespread in integrated circuit (IC) fabrications;
(1) Silicon dioxide can be the gate oxide of metal-oxide semiconductor (MOS) devices; PA1 (2) Silicon dioxide can be the field oxide to isolate itself from the other devices; PA1 (3) Silicon dioxide can be the trench isolation; PA1 (4) Silicon dioxide can be the masking for diffusion and ion implantation; PA1 (5) Silicon dioxide can be the capping film to prevent losing impurity or composite atoms after annealing; PA1 (6) Silicon dioxide can be the passivation film to protect the devices from the contamination of particles, dust and scratching, etc. PA1 (1) LPD-SiO.sub.2 can deposit a uniform and high density silicon dioxide film. PA1 (2) The growth temperature of the present invention is very low, thus the effect of high temperature to the wafers in the process can be eliminated. PA1 (3) System equipment is cheap and simple. PA1 (4) LPD-SiO.sub.2 is selective to the photoresist, thereby IC processes can be simplified.
With the advancing development of technology, so far there are many ways of growing silicon dioxide film, such as: thermal oxidation or chemical vapor deposition (CVD). Gate oxide and field oxide are fabricated by thermal oxidation since thermal oxidation is the only way to produce high quality oxide film with low interface densities. However, these two technologies, thermal oxidation and CVD, have fabrication limitations in industrial applications including: the use of high temperatures (700.degree. C..about.1200.degree. C.) during thermal oxidation that can easily result in the deformation of wafers and the damage to the device structure (due to the redistribution of dopants); and, in CVD, the drawbacks are its high equipment cost and growth temperature and need for more accurate control of the process conditions in mass production.
There are many ways of depositing silicon dioxide film at low temperature, such as: Plasma enhanced chemical vapor deposition (PECVD), Electron cyclotron resonance chemical vapor deposition (ECRCVD), etc. These depositions also need expensive system equipment and a growth temperature greater than 300.degree. C. Therefore it's impossible to shorten the process flow by using photoresist as a mask. Such factors limit the flexibility of IC process design. According to the reports by H. Nagayama, et al. in J. Electrochem. Soc., Vol. 135, pp. 2013 (1988) and A. Hishinuma, et al. in Applied Surface Sci., Vol. 48/49, pp. 405 (1991), Liquid phase deposition (LPD-SiO.sub.2) is a recently developed method of growing a silicon dioxide film. Unlike the traditional technology of growing silicon dioxide film which needs high growth temperature and expensive system equipment, the growth temperature of this technology is very low (about 40.degree. C.), and thus preferred for modem deep-submicron IC processes. However, so far there is no technology and method proposed for the mass production process of liquid phase deposition for the growth of silicon dioxide film (LPD-SiO.sub.2).